Note: gamma and beta are interchanged in slides.
```
Alpha = Have RB/WB and read values during RUN
Beta - with merge stage 
Gamma - with no merge stage (when key-pointers fit the memory)
Delta - Isolate compute and IO - Overlap reads and writes.
Epsilon - Merge overlap version 
RSW - RSW concurrency variatns
pmem_benchmark - The pmem benchmark suite
```